1. Field of the Invention
The present invention relates to a substrate processing apparatus which processes a substrate. Substrates to be processed include, for example, semiconductor wafers, liquid crystal display device substrates, plasma display substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, and photovoltaic cell substrates.
2. Description of Related Art
Japanese Patent Application Publication No. 2006-344907 discloses a single substrate processing type substrate processing apparatus that processes a substrate, such as a semiconductor wafer, etc., one by one. The substrate processing apparatus includes a spin chuck that rotates the substrate while holding the substrate horizontally and a nozzle that discharges a processing liquid of higher temperature than room temperature toward an upper surface central portion of the substrate held by the spin chuck. The high temperature processing liquid discharged from the nozzle lands on the upper surface central portion of the substrate and thereafter flows outward along the upper surface of the rotating substrate. The high temperature processing liquid is thereby supplied to an entire upper surface of the substrate.
The processing liquid that lands on the upper surface central portion of the rotating substrate flows from a central portion to a peripheral edge portion along the upper surface of the substrate. In this process, the temperature of the processing liquid decreases gradually. Temperature uniformity is thus decreased and processing uniformity is degraded. Although increasing a flow rate of the processing liquid discharged from the nozzle reduces the time taken for the processing liquid to reach the upper surface peripheral edge portion of the substrate and alleviates the lowering of the temperature of the processing liquid, in this case, the consumption amount of the processing liquid increases.